Example of how to add access to the Members page in Restrict Content Pro to the Editor role

gistfile1.php

<?php
function rcp_add_member_caps() {

	// gets the editor role
	$role = get_role( 'editor' );

	// Allow Editors to view Members in Restrict Content Pro
	$role->add_cap( 'rcp_view_members' );

}
add_action( 'admin_init', 'rcp_add_member_caps' );